Like someone said, go to Perlis. You can get 2 decent suits for that price (250-400 a piece) and lifetime alterations.
This is a good suggestion actually. I plan to purchase a couple Perlis suits in the near future.
As to the OP, I've never purchased from JoB but have only heard poor things: from materials, poor salesmanship, etc. to fit, only "old man cut" suits, etc.
To answer your question on tailoring, a good tailor will charge at least $100-125 to tailor an entire suit (jacket and pants) to your liking. So tack that on to anything you purchase off the rack anywhere if you want it to fit nicely.
The Stein Mart suggestion is actually money. I've purchased at least two suits (Tommy Hilfiger and Ralph Lauren) from there for less than $200 and had them tailored locally for around $100 and they fit great.